[FFmpeg-cvslog] avcodec/hevc_ps: Fix runtime error: signed integer overflow: 2147483628 + 256 cannot be represented in type 'int'

[Michael Niedermayer]

ffmpeg | branch: release/3.1 | Michael Niedermayer <michael at niedermayer.cc> | Wed May 31 22:02:07 2017 +0200| [317690375e78904e8bd11f4c0f46d8ddf29a8b65] | committer: Michael Niedermayer

avcodec/hevc_ps: Fix runtime error: signed integer overflow: 2147483628 + 256 cannot be represented in type 'int'

Fixes: 1909/clusterfuzz-testcase-minimized-6732072662073344

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 6726328f7940a76c43b4d97ac37ababf363d042f)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=317690375e78904e8bd11f4c0f46d8ddf29a8b65
---

 libavcodec/hevc_ps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/hevc_ps.c b/libavcodec/hevc_ps.c
index 83f2ec2bac..895046722f 100644
--- a/libavcodec/hevc_ps.c
+++ b/libavcodec/hevc_ps.c
@@ -738,7 +738,7 @@ static int scaling_list_data(GetBitContext *gb, AVCodecContext *avctx, ScalingLi
                                   ff_hevc_diag_scan8x8_x[i];
 
                     scaling_list_delta_coef = get_se_golomb(gb);
-                    next_coef = (next_coef + scaling_list_delta_coef + 256) % 256;
+                    next_coef = (next_coef + 256U + scaling_list_delta_coef) % 256;
                     sl->sl[size_id][matrix_id][pos] = next_coef;
                 }
             }